Isorhamnetin protects endothelial cells model CRL1730 from oxidative injury by hydrogen peroxide

To explore the protective effect and mechanism of isorhamnetin against oxidative injury caused by H2O2 to endothelial cell strain CRL1730 of human umbilical vein. H2O2 and endothelial cell strain CRL1730 were used, as a model of injured endothelial cell. Three levels of crude drugs areorhamnetin, 22.8µg/ml, 11.4µg/mL and 5.7µg/mL was added to the injured cell strain CRL1730 respectively. The cell injury was measured in terms of necrotic rate, quantities of von Wilebr and factor [vWf] and thrombomodulin [TM], lactate dehydrogenase [LDH] and intracellular free calciumions through flow cytometry, ELISA, fluorescent spectrometer and laser scanning confocal microscopy respectively. Isorhamnetins @ 11.4µg/mL and 5.7µg/mL has significantly decreased EC necrotic rate, while the increased vWf concentration due to oxidant [200mmol/L of H2O2] was significantly decreased by 5.7mg/mL versus 11.4 and 22.8mg/mL isorhamnetin. Also, the increased in TM and LDH in injured cells was reversed to normal level with 5.7 to 11.4mg/mL isorhamnetin. These results suggest that isorhamnetin protect the integrity of cell membranes. Similarly, H2O2 treatment of cells elicited the release of intracellular calcium, however, 5.7mg/mL and 11.4mg/mL isorhamnetin dramatically inhibited transient release of intracellular calcium. This suggests that isorhamnetin, at lower concentration, could inhibit the IP3-sensitive calcium pool from releasing calcium, protecting VECs from injury by H2O2. Traditional Chinese herbs, hippophaerhamnoides have been recognized as safe and as a source of flavonoids,with strong cardiovascular protection. The results of this study revealed that isorhamnetin produce a strong effect on some targetspresent in ECs and thus, provide a basis for the future work targeted towards endothelial cells protection

Pharmacokinetic study of isoquercitrin in rat plasma after intravenous administration at three different doses

The aim of this study is to develop a simple and specific HPLC method using vitexin as the internal standard to investigate the pharmacokinetics of isoquercitrin (ISOQ) after three different doses administrated intravenously to rats. The pharmacokinetic parameters were calculated by both compartmental and non-compartmental approaches. The results showed that ISOQ fitted a three-compartment open model. The values of AUC increased proportionally within the range of 5-10 mg·kg-1. Moreover, a half-life, b half-life, ªCL, MRT0-t and MRT0→∞ of ISOQ in rats showed significant differences between 20 mg·kg-1 and other doses, indicating that ISOQ presented dose-dependent pharmacokinetics in the range of 5-10 mg·kg-1 and non-linear pharmacokinetics at higher doses.

O objetivo deste estudo é desenvolver um método simples e específico de HPLC usando vitexina como padrão interno para investigar a farmacocinética do isoquercitrina (ISOQ) após três doses diferentes administradas por via intravenosa a ratos. Os parâmetros farmacocinéticos foram calculados pelas abordagens compartimental e não compartimental. Os resultados mostraram que ISOQ se encaixa no modelo de três compartimentos. Os valores de AUC aumentaram proporcionalmente na faixa de 5-10 mg·kg-1. Além disso, a meia-vida, b meia-vida, ªCL, MRT0-t and MRT0→∞ de ISOQ em ratos mostraram diferenças significativas entre 20 mg·kg-1 e outras doses, o que significa que ISOQ apresenta farmacocinética dose-dependente no intervalo de 5-10 mg·kg-1 e farmacocinética não linear em doses mais elevadas.

HPLC method for the simultaneous determination of four compounds in rat plasma after intravenous administration of Portulaca oleracea L. extract

The objective of the present study was to develop a simple and selective HPLC method for the simultaneous determination of hesperidin (HP), caffeic acid (CA), ferulic acid (FA) and p-coumaric acid (p-CA) in rat plasma after intravenous administration of Portulaca oleracea L. extract (POE). With the hyperoside as the internal standard, the sample pretreatment procedure involved simple single-step extraction with methanol of 0.2 mL plasma. The mobile phase consisted of methanol-acetonitrile-tetrahydrofuran-0.5% glacial acetic acid (5:3:18:74, v/v/v/v). The calibration curves were linear over the range of 0.1-25 µg mL-1, 0.1-25 µg mL-1, 0.1-25 µg mL-1and 0.015-3 µg mL-1 for HP, CA, FA and p-CA, respectively. The method developed was suitable for the pharmacokinetic study of HP, CA, FA and p-CA in rats after intravenous administration of POE.

O objetivo do estudo foi desenvolver um método simples e específico de HPLC para a determinação simultânea de hesperidina (HP), ácido caféico (CA), ácido ferúlico (FA) e ácido p-cumárico (p-CA) em plasma de rato após a administração intravenosa de extrato Portulaca oleracea L. (POE) empregando hyperosídeo como padrão interno de referência. Metanol foi empregado para os analitos em plasma (0,2 mL). A fase móvel isocrática foi composta por metanol-acetonitrila-tetraidrofurano-0,5% ácido acético glacial (5:3:18:74, v/v/v/v). Curvas de calibração foram lineares na faixa de concentração de 0,1-25 µg mL-1, 0,1-25 µg mL-1, 0,1-25 µg mL-1 e 0,015-3 µg mL-1 para HP, CA, FA e p-CA, respectivamente. O método desenvolvido foi adequado para estudo farmacocinético de HP, CA, FA e p-CA em ratos após a administração intravenosa de POE.